The present invention relates to a mobile self-propelled apparatus for progressively sandblasting over a surface.
Sandblasting of inanimate surfaces has conventionally been done by passing air from a compressor through an air line, into a sand pot holding sand, and then through a sand hose through a nozzle which is handled manually by a worker who directs the nozzle in an appropriate fashion against an appropriate area of the surface to be treated. Such a conventional method of sandblasting has many inherent disadvantages, including the fact that the clouds of silica dust generated in the vicinity of the surface being treated are quite harmful to the worker holding the nozzle. Also, the efficiency of the operation as well as uniformity of the treatment of the surface depend to a large degree upon the skill of the worker.
U.S. Pat. No. 4,255,906 to Hockett issued Mar. 17, 1981 describes and illustrates an abrasive cleaning apparatus, for sandblasting and the like, comprising a multi-nozzle head mounted on a swinging boom arm which is in turn supported on a mobile chassis. The boom arm pivots on the chassis about a vertical axis and about a horizontal axis. A winch mechanism provides linear advancement of the mobile chassis over a surface, controlled with the sweep of the swinging boom arm.
U.S. Pat. No. 4,126,970 to Hockett issued Nov. 28, 1978 describes and illustrates an abrasive cleaning apparatus of somewhat similar nature which is mounted on a mobile chassis but which is not self-propelled.
Other patents of background interest include Canadian Patent No. 1,114,170 of Neidigh et al., issued Dec. 15, 1981 (blast cleaning device for storage tanks comprising a wheeled travel car suspended from the sides of the tanks by means of a rigging), U.S. Pat. No. 4,309,850 to Benson issued Jan. 12, 1982 (portable sandblasting apparatus drawn on a truck along a desired path, with sandblasting nozzles reciprocating from side-to-side), U.S. Pat. No. 4,064,656 issued Dec. 27, 1977 (rail mounted swinging boom arm supporting a sandblasting nozzle), Canadian Patent No. 834,430 of Dye issued Feb. 17, 1970 (electrically controlled device for positioning a nozzle such as that of a sandblasting machine) and U.S. Pat. No. 4,139,969 to Brown issued Feb. 20, 1979 (apparatus for automatically controlling the feed rate or advancement of a grinding wheel into a workpiece).
It is an object of the present invention to provide an improved mobile self-propelled apparatus for automatically progressively sandblasting over a surface. It is a further object of the present invention to make such device, when operating, fully automatic and to run on energy from the air compressor used for supplying compressed air to the sandblasting nozzle.